(a) Technical Field
The present invention relates to a dye-sensitized solar cell module and a method of manufacturing the same. More particularly, it relates to a large-area dye-sensitized solar cell module which can reduce the weight of the cell without degrading performance by reducing the thickness thereof using a thin glass plate substrate, and a method of manufacturing the same.
(b) Background Art
In recent years, as global warming is becoming a serious problem, technologies for utilizing environmentally friendly energies have begun to emerge as a necessity in the future growth of energy sources. In particular, solar cells have been significantly beneficial because they utilize renewable energy. These solar cells include silicon solar cells, thin film solar cells using inorganic materials such as copper indium gallium selenide (CIGS)(Cu(InGa)Se2) and cadmium telluride (CdTe), dye-sensitized solar cells, organic solar cells, and organic-inorganic hybrid solar cell.
Among the solar cells, silicon solar cells have already been widely used commercially in various fields such as houses and industrial plants, but their price and installation costs are prohibitively expensive for smaller applications. However, dye-sensitized solar cells are inexpensive compared to silicon solar cells and can achieve semi-transparent designs or other various designs. Therefore, many studies on the dye-sensitized solar cells are being made.
More specifically, dye-sensitized solar cells may be applied not only to houses but also to building integrated photovoltaic power generation systems like silicon solar cells, and may be applied to various fields including electronic industrial fields such as home appliances and portable electronic devices, and roofs and glass windows for vehicles. Such a dye-sensitized solar cell includes a system for generating electricity by using a photoelectric conversion mechanism configured to absorb visible light from a Ru-based pigment adsorbed to a TiO2 and form a photocurrent.
FIG. 1 is a sectional view illustrating a conventional dye-sensitized solar cell module. As illustrated in FIG. 1, the dye-sensitized solar cell module 1 includes a working electrode 10 on which a photo-electrode 13, to a which a dye is adsorbed, is stacked, a counter electrode 20 on which a catalytic electrode 23 is stacked, and an electrolyte 30 filled within a sealed space between the working electrode 10 and the counter electrode 20.
The example of the dye-sensitized solar cell module 1 includes a dye-sensitized solar cell module 1 where a photo-electrode 13 (or a semiconductor oxide thick film) such as TiO2, to which a Ru-based dye capable of absorbing light, is stacked on a transparent conductive substrate 11a of a working electrode 10. A catalytic electrode 23 using platinum Pt is stacked on a transparent conductive substrate 21a of a counter electrode 20, and an I−/I3−-based electrolyte 30 is filled in a space between the working electrode 10 and the counter electrode 20 sealed by a sealant 31 with the working electrode 10 and the counter electrode 20 which are bonded to each other.
A collector may be formed in an interior of the dye-sensitized solar cell module to acquire necessary electric power by applying the dye-sensitized solar cell module to applications, making it possible to effectively collect a photocurrent. Then, an overall efficiency of a dye-sensitized solar cell is influenced by the size of a collector and a photo-electrode in a working electrode when modules are manufactured through the same process. Accordingly, many studies on structures of dye-sensitized solar cell modules including components, shapes, and dispositions of collectors have been conducted to provide the most efficient cells. In particular, a collector capable of collecting a photocurrent may be used in order to apply a dye-sensitized solar cell to an application over a large area.
In FIG. 1, the reference numeral 11 denotes a substrate of the working electrode 10, the reference numeral 12 denotes a transparent electrode material layer (FTO, Fluorine Doped Tin Oxide (SnO2:F)) formed on the substrate 11, the reference numeral 21 denotes a substrate of the counter electrode 20, and the reference numeral 22 denotes a transparent electrode material layer formed on the substrate 21. Furthermore, the reference numeral 25 denotes a portion of the collector 24a exposed to the outside of the module 1, i.e. a collector bottom portion 25 of the counter electrode 20.
FIG. 2 is a view illustrating an example of forming a collector 14a in the working electrode 10. The collector 14a includes collector cells 14 surrounded by a protective film 16, and a collector bottom portion 15 to which the collector cells 14 are connected. More specifically, as illustrated in FIG. 2, in a general dye-sensitized solar cell module having the collector 14a, the silver collector cells 14 surrounded by the protective films 16 interposed between the collector cells 14 and the TiO2 photo-electrode 13 are formed in a line on the transparent conductive substrate 11a. Then, the collector cells 14 extend to the collector bottom portion 15 stacked along a periphery of the transparent conductive substrate 11a to be integrally connected to each other.
Likewise, although not illustrated in the drawings, thin collector cells surrounded by a protective film interposed between the collector cells and the catalytic electrode 23 are formed in the counter electrode 20. The collector cells extend to the collector bottom portion 25 (see FIG. 1) stacked along a periphery of the counter electrode 20 to be integrally connected to each other.
As illustrated in FIG. 1, the collector bottom portions 15 and 25 are exposed to the outside of the module 10 in the electrodes 10 and 20, and act as electrode portions electrically connecting adjacent modules when a solar cell module is constructed by using a plurality of solar cell modules 1.
The transparent conductive substrates 11a and 21a used for the working electrode 10 and the counter electrode 20 are manufactured by stacking a transparent electrode material, e.g., FTO on glass substrates 11 and 21 consisting of soda-lime glass, in which case the thickness of the glass substrates 11 and 21 is about 2 to 3 mm.
However, since the weight of the dye-sensitized solar cell module 1 tends to increase as the side thereof becomes larger, there is a need to reduce the weight of the module when the module is applied to application products such as a roof (e.g., a sunroof and a panorama roof) of a vehicle, a sun visor for a vehicular glass window, and other electronic products.
Although a dye-sensitized solar cell may be manufactured by using a flexible substrate in order to solve this problem, a performance of a dye-sensitized solar cell using a flexible substrate is degraded in comparison with a dye-sensitized solar cell which uses a conventional glass substrate.
Korean Patent Application Publication No. 2009-0067416 discloses a technology for applying a solar cell film using a flexible substrate to a vehicle in which a solar cell film is inserted into a glass window. However, although this flexible substrate is lighter than a glass substrate, and it is impossible to heat-treat the flexible substrate in an aspect of processing, a solar cell using a flexible substrate has performance characteristics which are much lower than that of a solar cell using a glass substrate and the utility of the solar cell using a flexible substrate is thus degraded.